The present invention relates generally to clutch release bearings, that is to say the assembly intended to act on the release device of a clutch, particularly for motor vehicles.
Known clutch release bearings generally comprise an operating element, which is intended to be subjected to the action of a control member such as a clutch release fork, and a drive element, which is intended by the action of the operating element to act upon the release device of the clutch, and which is freely rotatable but axially fixed relative to the operating element.
The present invention concerns more particularly those clutch release bearings in which the axial connection of the drive element to the operating element is provided by means of a connecting cap, this connecting cap comprising for that purpose, a plurality of axial lugs by which it is attached to the operating element, and a front wall which forms an axially-acting resilient means which bears on the drive element and urges the latter against the operating element.
A clutch release bearing of this kind is described in French Pat. No 2,337,281. The construction described in this French Patent concerns a so-called self-centering clutch release bearing, in which the drive element is allowed to universal freedom of movement radially with reference to the operating element, and the operating element is made from plastics material and incorporates an annular flange. The drive element is maintained resiliently in contact with this annular flange, on one side of the latter, by the connecting cap. The control member acts on the other side of this annular flange.
The control member is generally made from metallic material, and in order to prevent this control member from damaging the annular flange of the operating element, which is made of plastics, the annular flange is lined on its surface with a support plate adapted for contact with the control member.
According to the arrangements described in the above-mentioned French patent, this support plate is utilised in order to effect the fastening of the connecting cap; on the circumference of the support plate that are provided engagement spurs projecting at intervals upon which the axial lugs of the connecting cap are engaged, these axial lugs each being formed with an aperture by which it can be engaged on a respective engagement spur.
In practice, for an appropriate radial maintenance of the axial lugs of the connecting cap, i.e. in order to prevent these connecting lugs from escaping radially from the engagement spurs on which they are engaged, with the danger of the drive element becoming detached from the operating element, the engagement spurs are at least slightly curved to provide a hook-shaped configuration.
This arrangement, which has given and continues to give satisfactory performance, is however only acceptable in practice when it is possible to form the hook-shaped curved engagement spurs on the relevant support plate without difficulty, i.e. in so far as this support plate is sufficiently thin to be easily shaped.
This is the case e.g. where the control member acts upon the operating element along a circumference of substantially equal diameter to that of the circumference over which the drive element bears on the operating element, and the support plate associated with the latter has the simple function of a wearing plate; not being subject to any flexing, it can be made of thin sheet metal.
This is not the case where the control member acts upon the operating element along a circumference of much greater diameter than that of the circumference over which the drive element bears on the operating element.
In this case, the support plate associated with the operating element laterally overhangs the latter considerably in order to enable the control member to grip it, and is therefore no longer checked by the operating element in line with such a grip.
In order to prevent any undesirable flexing of the support plate in this case, it is necessary to stiffen it, and therefore in practice to make it thicker.
It is then much more difficult to form the engagement spurs necessary for fastening the connecting cap. The same applies where the operating element is in itself a metallic part and is therefore not lined by a support plate.
The object of the present invention is to provide an arrangement which permits an appropriate fastening of the connecting cap in such cases.